Signs towards Sustrans routes to help divert cyclists away from the dangerous A2 dual carriageway.
However, the routes shown aren't totally accurate. All of the best routes for these destinations will head towards and onto NCR18. First, turn right onto the A28 at the traffic lights (walk across using the nearby controlled crossing if needed), then turn left into Ten Perch Road. Head across at the first roundabout, then almost across (11 o'clock position) onto shared cycle path at the second roundabout. This leads to NCR18 (Great Stour Way). At the T-junction with the Great Stour Way, turn left to head towards Chartham and Ashford. Turn right to head into Canterbury and towards Whitstable (via NCR1) and RCR16 (via NCR1 bound towards Sandwich (Not towards Whitstable when you see the signs)).
The pictured sign needs correcting, and the onward signs need to be added, since they're not present.